Experimental Evaluation and Modeling of Waste Heat Recovery in VECTO

Waste heat recovery based on an Organic Rankine Cycle is a technology proposed for the reduction of the fuel consumption of heavy-duty vehicles. This technology is currently not simulated by VECTO, the tool used in Europe to certify the fuel consumption and CO₂ emissions of new heavy-duty vehicles. In this work, a class 5 lorry equipped with a prototype Organic Rankine Cycle system is tested on the chassis dyno during steady state and transient driving cycles, with the waste heat recovery enabled and disabled. The waste heat recovery system enabled a brake specific fuel consumption reduction of 3.1% over the World Harmonized Vehicle Cycle, 2.5% during the official EU Regional Delivery Cycle, and up to 6.5% at certain engine operating points during the fuel consumption mapping cycle. A model of the vehicle was created in VECTO based on the experimental data. The fuel consumption map of the engine with and without the Organic Rankine Cycle was derived from the steady-state experiments. Multiple modelling approaches to simulate the vehicle fuel consumption with waste heat recovery were evaluated. Comparing the simulation results with the experimental data, showed that VECTO was able to predict the fuel consumption with an error of 0.34% for the regional delivery cycle. Finally, the model was used to predict the fuel consumption reduction with waste heat recovery for all regulatory driving cycles in VECTO.